We must transition to a resilient electricity system

Three decades ago, in 1982, the American energy visionary Amory Lovins and his wife Hunter published Brittle Power, a study commissioned by the civil defence arm of the Pentagon. It was an alarming analysis of the vulnerability of US systems, in particular, US energy systems, to disruption, by mishap or malice. But it also indicated many ways to reduce that vulnerability. Ever since then the US military has played a leading role in transforming traditional energy systems, and especially electricity systems, to make them more robust and resilient. Curiously enough, however, the civilian side of US electricity has lagged well behind. So have electricity systems elsewhere. As the threats continue to mount, so do the opportunities. Three decades later, traditional electricity is long overdue for an upgrade.

Traditional electricity is based on design criteria now more than a century old, out of date and obsolete. It arose because of the economies of scale of steam power and water power, the only prime movers then available. Throughout the most of the twentieth century, a better power station was always thought to be a bigger power station, farther away. The common technical model replicated all over the world, is based on large, remotely-sited, central-station generators, most of which operate either intermittently or at only partial load most of the time. If a single one of such huge units fails, the shock could bring down the whole system. Accordingly, the system has to have at least one spare unit of the maximum size, running but not generating, to provide emergency backup, so-called ‘spinning reserve’.

The central-station generators that use fuel waste two-thirds of the fuel energy before it even leaves the power plant. The arrangement necessitates long lines of the network, in which line losses cost another significant fraction of the energy flowing. The configuration is inherently vulnerable to disruption over a wide area and almost instantaneously. Despite what politicians would have you believe, electricity is not a commodity. It is a process, happening in technology. If the process is interrupted anywhere on the system it may be disrupted everywhere, within seconds. For example, on 14 August 2003, a tree fell in Ohio, bringing down a transmission line. The electricity diverted to a neighbouring line, overloading it. Protective devices broke that circuit too. In a matter of moments, a cascading collapse left some 50 million people in the northeastern US and Canada without electricity. Nearly two weeks passed before supply was back to normal. That was spectacular, but far from unique. The blackouts we hear about, in the rich parts of the world, are all too common; but they are far outnumbered by those we do not hear about.

In recent years the constraints on traditional electricity have tightened yet further. In many major cities the underground cables are now fifty, sixty, seventy or more years old, overloaded and deteriorating, yet almost impossible to replace. Permission for wayleaves for new overhead transmission lines is now politically explosive, nearly unobtainable essentially everywhere. Traditional coal-fired and nuclear-generating plants anywhere except in centrally-planned countries are both financially and environmentally intensely controversial, and growing steadily more so. Keeping the lights on is getting progressively more difficult.

If we were starting now to electrify society, with what we now know about technology, finance, politics and environment, the resulting electricity systems would look unrecognisably different. Better generators can now be smaller, cleaner, more efficient units closer to users, and indeed even on the same premises. Gas-fired micro cogeneration using gas engines is already long since well-established, providing electricity, heating and sometimes also cooling, from the same amount of fuel, by a unit in the cellar of an office building, hotel, hospital or shopping mall. Such installations do not even require on-site maintenance. Heavily instrumented, they send information about their performance to a control centre that may even be in another town. Any sign of drift alerts a field technician, who will probably rectify the problem before the users of the building even notice it. The units may be purchased or leased, or the customer may pay a service contract or simply buy the electricity, heat and cooling provided.

The concept of on-site and local provision of electricity, heat and cooling has enormous potential. Local systems can now also include wind turbines, photovoltaic arrays, solar thermal arrays, geothermal wells, heat pumps, microturbines and fuel cells, either already or soon to be similarly economic, clean and convenient. Smaller units pose much less of a threat to the system in case of failures or faults. Moreover, if you are generating your own electricity you are much less likely to waste it. An integrated local system will foster high-performance user-technology and user-infrastructure, by directing investment into the optimal balance of system assets, making sure the user-technology, especially the building, is high quality before even thinking of generation. Sensing and control technology can allow generation and loads both to interact in real time, making such a system self-stabilising.

Local systems need not be completely isolated. Some interconnection through longer lines will still be valuable, for backup and to feed in electricity from more remote installations such as offshore wind. But these longer lines will now be of secondary importance. The main source of faults on a traditional electricity system is the network. Reducing its size, and eliminating many of the long lines, will reduce dramatically the likelihood of large-scale system breakdown. At the same time, converting some of the long lines to high-voltage direct current or HVDC can double or even triple the carrying capacity of the line, with the same conductors and towers. DC operation for some circuits, and back-to-back AC-DC-AC linkages with power electronics will block the troublesome transient disturbances that can travel thousands of kilometers in a flash on AC lines but are stopped completely by DC.

Decentralising and optimising electricity systems to make them more resilient also has yet more profound implications. We hear a lot about what people call energy problems, about global ‘energy security’ and climate. But these problems are not about ‘energy’. They are quite specifically about fuel. What causes our problems of supply security and disturbance of the climate is the way we use and depend on fuel. The rational response would be to reduce our dependence on fuel. We can do so in two ways, parallel and complementary. One is to stop wasting it, by investing to upgrade user-technology, especially buildings – the most important energy technology of all. The other is to recognise that we use two kinds of electricity. One is based on fuel – coal, oil, natural gas or uranium. The other does not use fuel. Instead you invest to set up a physical asset – a hydroelectric generator, a wind turbine, a photovoltaic array or solar thermal array, a geothermal well, a marine installation – to harvest natural ambient energy flows and turn them into useful electricity.

Most people call this electricity ‘renewable’. A better term is ‘infrastructure electricity’. As with upgrading user-technology, infrastructure electricity entails an initial investment, after which the infrastructure delivers the service, with minimal subsequent running cost. Such an arrangement, much less dependent on fuel, is also much less vulnerable to disruption – more robust and resilient. The US military is demonstrably following this precept. Delivering fuel to a war zone costs not only money but lives. US military planners have long since endeavoured to minimise what would otherwise be daunting and dangerous dependence on fuel, by making their base buildings and other facilities as high-performance as possible, and by installing local infrastructure electricity generation. The example is there. Sensible energy policy, for civilians as well as the military, ought to function accordingly. A sustainable energy future starts with robust, resilient local systems and infrastructure electricity.